Re: [Elecraft] KX2 Offset I.F.

For me a software-defined receiver is one where the demodulators and filters are implemented (defined) in software. Adding a synchronous AM detector is 100% software. We already have precise terms for receiver architectures: superhet, direct conversion, and TRF (no conversion). Direct sampling

Re: [Elecraft] KX2 Offset I.F.

Don, I'm not sure there IS an accepted definition of a "Full SDR" radio, but it's just a matter of semantics, anyway.  I just wanted to point out that the KX2 and KX3 use local oscillators and mixers to convert the RF to the IF, like any superhet.  From there, it's pure SDR.  (Perhaps aside

Re: [Elecraft] KX2 Offset I.F.

Scott, By your definition of an SDR, that may be true. Some SDRs today are direct sampling at the antenna, but think back to SDRs in the recent past when high frequency direct sampling was only achieved at great cost - the simplest example is the SoftRock 40 which used a quadrature mixer to

Re: [Elecraft] KX2 Offset I.F.

On 12/22/2017 11:37, Don Wilhelm wrote: Of course, the KX2 is *not* a superhet, it is a full SDR.  If the "IF" were at a higher frequency, the VFO would be further away from the signal frequency - by the frequency of the IF. I must disagree.  All the digital processing takes place after the

Re: [Elecraft] KX2 Offset I.F.

This sounds like a fun area to study, Thanks for putting me on the path. I will look up KK7B's work. KV4TT - Mike On Fri, Dec 22, 2017 at 12:37 PM, Don Wilhelm wrote: > Mike, > > Think of the 8kHz shift similar to a low frequency (8kHz) IF if your > thinking is along

Re: [Elecraft] KX2 Offset I.F.

Mike, Think of the 8kHz shift similar to a low frequency (8kHz) IF if your thinking is along the lines of a superhet receiver. Of course, the KX2 is *not* a superhet, it is a full SDR. If the "IF" were at a higher frequency, the VFO would be further away from the signal frequency - by the

Re: [Elecraft] KX2 Offset I.F.

Hi Don, Thank you for the great explanation. I must have had the ATT on when I did the original power measurement (rough) on the SDR I tested again and this time I get: -77dBm - Preamp On -55dBm - Preamp Off -74dBm - ATT on Just relative differences with the absolutes unique to my setup of

Re: [Elecraft] KX2 Offset I.F.

Mike, The KX2 is fully an SDR with the "computer" in the enclosure. Yes, it has a permanent 8kHz shift, so all the DSP operation is conducted at 8kHz (not audio), including the nulling and suppression. You are hearing the actual VFO freuency - it is 8kHz from the operating frequency of the

[Elecraft] KX2 Offset I.F.

Hello group, I received a new KX2 from Elecraft a few days ago and I am really enjoying the little GEM! As many of you already must know, the receiver performs brilliantly. I have been comparing with a couple of SDR receivers in the shack and the KX2 is preferred for weak signal reception in